Engine Fail-Safe Device Torque Estimation Abnormal Temperature
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Solution Overview
Problem
Existing fail-safe devices for engines may lose functionality when temperature parameters indicate abnormal values, leading to unintended acceleration due to incorrect estimation of engine generation torque.
Innovation Solution
A fail-safe device with a temperature setting module that maintains a current set value of temperature parameters when input values exceed a predetermined change amount restrictive value, updating the set value only when the difference returns within the restrictive value, and increasing the restrictive value based on consecutive exceedances, ensuring accurate torque estimation and preventing sudden acceleration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the temperature parameter input value is used directly in torque estimation, then the torque estimation responds quickly to temperature changes, but the fail-safe function is lost when the input value becomes abnormal
Solution Approach 1:
The patent applies preliminary action by setting a restrictive value in advance before abnormal values can affect torque estimation. The restrictive value is predetermined based on normal operating conditions, and the system checks whether the temperature parameter change exceeds this restrictive value before using it in torque estimation. This prevents abnormal values from being used while still allowing normal temperature variations to be reflected in the torque estimation.
Solution Approach 2:
The patent introduces an intermediary mechanism (the restrictive value check) between the temperature parameter input and the torque estimation calculation. This intermediary layer filters out abnormal values by comparing the temperature parameter change against the restrictive value, allowing only valid changes to pass through to the torque estimation, thus protecting the fail-safe function while maintaining responsiveness to legitimate temperature changes.
2Adaptability or versatility
If the restrictive value is increased to allow more temperature variation, then the system becomes more adaptable to temperature changes, but abnormal values may slip through and cause unintended acceleration
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the restrictive value based on engine operating conditions. The restrictive value is not fixed but is determined according to the engine state (such as engine speed, load, and temperature), allowing the system to adapt to different operating conditions while maintaining appropriate safety margins. This ensures that normal temperature variations are accommodated while still preventing abnormal values from causing unintended acceleration.
Data Source
AI summary
A fail safe device of an engine includes: a temperature setting module; a torque estimation module; and a torque monitoring module. The temperature setting module sets a value of a predetermined temperature parameter used in an estimation of a generation torque of the engine. The torque estimation module estimates the generation torque of the engine by using a set value of the predetermined temperature parameter set by the temperature setting module. The torque monitoring module decreases the generation torque of the engine, when the generation torque estimated by the torque estimation module is larger than a driver expected torque by a predetermined value or more.